Network Switch that is Optimized for a Telephony-Capable Endpoint

ABSTRACT

A method is disclosed that enables the avoidance of a processor overload of a telecommunications endpoint device that is susceptible to traffic floods. An enhanced network switch sets the speed on one of its data ports as a specific function of the speeds of the devices that are connected to one or more of its other data ports. This behavior is different from that of network switches in the prior art, in which the data rate of a port in the prior art is auto-negotiated to the highest speed that can be supported by the network elements at either end of the port&#39;s connection, regardless of the other devices present. By considering the specific devices that are connected, the enhanced network switch is able to limit the amount of traffic that is directed by an upstream device, such as a router, towards a device with limited processor capability, such as a packet-based phone.

FIELD OF THE INVENTION

The present invention relates to telecommunications in general, and,more particularly, to mitigating the effects of a packet attack on atelephony-capable endpoint that is connected to a network switch.

BACKGROUND OF THE INVENTION

FIG. 1 depicts a schematic diagram of telecommunications system 100 inthe prior art. System 100 routes voice conversations, or other types ofmedia such as video, between telephony-capable network elements such astelephones. System 100 comprises network switch 101, router 102,Internet Protocol packet network 103, and endpoint network elements104-1 through 104-M, wherein M is a positive integer. The elementsdepicted in FIG. 1 are interconnected as shown. In FIG. 1, two types ofnetworks are represented: an Internet Protocol (IP) packet network,which is depicted by network 103, and a local area network (or “LAN”),which comprises network switch 101 and the network elements that areconnected to the switch.

Network switch 101 is a networking device that provides for the localdistribution of signals. Switch 101 distributes the signals by filteringand forwarding packets between segments in the local area network thatthe switch serves. Switch 101 comprises a plurality of data connectionports and relays traffic from one connection port to another other in atransparent manner. At most, one network element is connected to anyport at switch 101; in this way, switch 101 is distinguished fromanother type of networking device called a bridge, in that a bridge canhave more than one network element that uses the same connection port.Switch 101 operates in accordance with the networking protocol of theparticular local area network that it serves, which in this case is theEthernet protocol.

Since the only devices on each LAN segment are switch 101 and thenetwork element node connected to each port, switch 101 picks up everytransmitted packet before the packet reaches another node. The switchthen forwards the packet over the appropriate segment. Since any segmentcontains only a single node, the packet only reaches the intendedrecipient and does not interfere with the transmission of another packetby another node, thereby enabling many calls to occur simultaneously.

In typical use, one of the ports of switch 101 is connected to a router,such as router 102 described below, or to another switch. It is thisport through which endpoint network elements 104-1 through 104-M gainaccess to another network than the network served by network switch 101.Note that there is nothing unique about the port to which the router isconnected—that is, the port to which the router is connected can be anyof the ports of switch 101.

Router 102 is a networking device that forwards data packets alongnetworks, in this case between the local area network served by networkswitch 101 and Internet Protocol packet network 103. Router 102 routespackets at the network layer (i.e., layer 3) of the Open SystemInterconnection (OSI) reference model. As a device that is closer to a“backbone” network, such as Internet Protocol packet network 103described below, router 102 is considered to be an “upstream device” oris referred to as being “upstream” of network switch 101.

Internet Protocol packet network 103 is a backbone network that is usedto transport one or more types of media, such as Voice over InternetProtocol (or “VoIP”). Network 103 comprises one or moretransmission-related nodes such as routers that are used to direct datapackets (e.g., voice packets, etc.) from one or more sources to thecorrect destinations of those packets. Network 103 is capable ofhandling Internet Protocol-based messages that are transmitted among thenetwork elements that have access to network 103, such as the endpointnetwork elements and gateways (not shown). Although IP network 103 asdepicted is a Voice-over-IP service provider's network, network 103could alternatively be the Internet or some other type of InternetProtocol-based network.

Endpoint network element 104-m, for m=1 through M, is a local areanetwork-based device such as a telephone, (e.g., deskset, softphone,etc.), a computer (e.g., desktop computer, portable computer, etc.), andso forth. As an endpoint, network element 104-m enables its user toaccess other devices throughout telecommunications system 100, such ashost computers or other endpoints that are accessible to network element104-m only through IP packet network 103.

In order to support each endpoint network element 104-m that isconnected to it, network switch 101 has to be able to communicate witheach connected device through a communication protocol such as Ethernetthat the connected devices and switch 101 all recognize. The Ethernetstandard that governs network switch 101 supports different speeds ofoperation at the switch, including 10 Megabits/second, 100Megabits/second, and 1 Gigabit/second. Modern network interface cards(or “NIC”) can operate at more than one of these standard speeds. Forexample, a “10/100” NIC can operate at either 10 Megabits/second or 100Megabits/second. The actual speed of operation is set either byconfiguration or by a process known as auto-negotiation. Inauto-negotiation, the NICs of the elements at either end of eachconnection set the speed based on the fastest rate that can be supportedby both. Thus, a 10/100/1G NIC and a 10/100 NIC will settle upon 100Megabits/second through auto-negotiation. Alternatively, the 10/100 NICat either end can be manually pegged to operate at 10 Megabits/second,in which case the pair of NICs will then settle upon 10 Megabits/secondas the common speed of operation. Furthermore, each connection willauto-negotiate its own rate, independent of what is connected to theother ports at switch 101. For example, the link to router 102 mightsettle on 100 Megabits/second, while the link to network element 104-1might settle at 10 Megabits/second, while the link to network element104-2 might settle at 100 Megabits/second.

An endpoint device, such as network element 104-1, often comprises aprocessor (i.e., a central processing unit) that is able to handle apacket transfer rate (both incoming and outgoing packets) that isconsidered normal, such as a transfer rate that is specified for aparticular mode of real-time voice communication. However, the sameprocessor often cannot handle a packet transfer rate that is associatedwith a sustained burst of packets, such as during a traffic flood thatis either malicious or inadvertent in nature. In addition, the endpointdevice's network interface card is typically able to handle aconsiderably higher influx of packets than the same device's processoris able to handle. Consequently, processor overload can occur when anend-user device is abnormally flooded with packets, if both the upstreamlink to router 102 and the link to the endpoint device (e.g., networkelement 104-5, etc.) have settled at any rate that is higher than whatthe endpoint device's processor is able to handle. Overloading theprocessor can have undesirable consequences for the operation of theendpoint device as a user's telephony device.

What is needed is a way to avoid overloading an endpoint's processorwith packets, without some of the disadvantages in the prior art.

SUMMARY OF THE INVENTION

The present invention enables an avoidance of a processor overload at atelecommunications endpoint device that is susceptible to trafficfloods. In accordance with the illustrative embodiment of the presentinvention, an enhanced network switch sets the speed at one of its dataports—for instance, at a data port reserved for an upstream device suchas a router—as a specific function of the speeds of the devices that areconnected to one or more of its other data ports. By setting the speedof the data port for the upstream device as both a function of the otherdevices connected and their speeds, the enhanced network switch of theillustrative embodiment is able to limit the amount of traffic that isdirected by the upstream device towards a device with limited processorcapability, such as a packet-based phone. For example, depending on theother devices present, the network switch will select the lowest rate incommon between itself and the upstream device, or at most a rate that isstill sufficiently low enough to avoid overloading the phone'sprocessor. This behavior is different from that of some network switchesin the prior art, in which the data rate of a port in the prior art isauto-negotiated to the highest speed that can be supported by thenetwork elements at either end of the port's connection, regardless ofthe other devices present.

The present invention recognizes that the data rate of the networkinterface unit of a packet-based phone is often disproportionately high,relative to the low processing power of the phone's central processingunit. Under normal operating conditions, this disproportion does notpose a problem because the normal data rate of incoming packets isadequately handled by the phone's processor. However, when the phone isstruck with a packet flood, the phone's processor is often incapable ofhandling the flood data rate, even though the phone's network interfaceis still able to handle the flood data rate. The processor overloadproblem can be mitigated in the prior art by manually configuring theupstream link to operate a lower data rate, thereby limiting the rate atwhich packets are presented to the phone. Unfortunately, the prior-arttechnique has the disadvantage of unnecessarily constraining otherconnected devices to exchange data with the packet network at the lowerrate.

In accordance with the illustrative embodiment, the enhanced networkswitch receives signals from two or more devices being that areconnected to the switch, as part of the auto-negotiation process. Insome circumstances, the switch sets the speed of the link with theupstream device to the lowest rate supported. Selecting the lowest rateis based on the presence of a particular network element, such as aphone with a marginal processor, or on a device being plugged into aparticular port, such as a port marked “phone”. In some embodiments,when a third network element such as a personal computer is connected tothe network switch, the auto-negotiation rules in the prior art canoverride the rules of the illustrative embodiment; in this way, thethird network element is not penalized in terms of the allowable datarate of packets from the packet network. In some other embodiments, thereceive-path link from the upstream device of a full-duplex link can beset to the lowest rate to prevent processor overload, while thetransmit-path link can independently be set at the highest rate withoutan adverse effect on the phone's processor.

The present invention technique, in contrast to the prior art, takesadvantage of the fact that upstream network elements tend to bededicated, high-speed switches or routers with much greater processingcapability than a phone and are able to handle much higher rates oftraffic. In other words, the enhanced network switch of the illustrativeembodiment shifts the responsibility of dealing with a packet flood,whenever possible, to the upstream device.

The illustrative embodiment of the present invention comprises:receiving, at a network switch, a first signal from a first networkelement and a second signal from a second network element, wherein thefirst network element is connected to a first data port at the networkswitch, and wherein the second network element is connected to a seconddata port at the network switch; determining that the first networkelement and the second network element are each capable of communicatingat least at a first data rate and a second data rate, wherein the firstdata rate is less than the second data rate; and establishing a link atthe first data rate between the first network element and the networkswitch, wherein the first data rate is selected over the second datarate based on at least one of: (i) a network element being connected tothe second data port, wherein the second data port is predetermined, and(ii) the second network element being connected to the network switch,wherein the second network element is predetermined.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts telecommunication system 100 in the prior art.

FIG. 2 depicts telecommunication system 200, in accordance with theillustrative embodiment of the present invention.

FIG. 3 depicts the salient components of enhanced network switch 211 ofsystem 200.

FIGS. 4A and 4B (in combination, referred to as “FIG. 4”) depict aflowchart of the salient tasks that are executed by enhanced networkswitch 211, in accordance with the illustrative embodiment of thepresent invention.

DETAILED DESCRIPTION

The term “network element,” and its inflected forms, is defined for usein this specification, including the appended claims, as atelecommunications device that is addressable. A network element can bean endpoint device such as a packet-based telephone, a host device suchas a computer server, or a networking device such as a switch or router.

FIG. 2 depicts telecommunication system 200, in accordance with theillustrative embodiment of the present invention. System 200 comprisesrouter 102, Internet Protocol (IP) packet network 103, and networkelements 104-1 through 104-N, wherein N is a positive integer, as wellas enhanced network switch 211 and IP-capable phone 212. The elementsdepicted in FIG. 2 are interconnected as shown. Router 102, IP packetnetwork 103, and network elements 104-1 through 104-N are describedabove and with respect to FIG. 1.

Two types of networks are represented in FIG. 2. The first is anInternet Protocol (IP) packet network, which is depicted by network 103.The second is a local area network (or “LAN”). The local area networkcomprises enhanced network switch 211 and the network elements that areconnected to the switch (i.e., network elements 104-1 through 104-N andIP phone 212). As those who are skilled in the art will appreciate,other local area networks that serve other network elements can beconnected to IP packet network 103.

Enhanced network switch 211 is a networking device that provides for thelocal distribution of signals, in accordance with the illustrativeembodiment of the present invention, the salient components of which aredescribed below and with respect to FIG. 3. Switch 211 distributes thesignals by filtering and forwarding packets between segments in thelocal area network that the switch serves. Switch 211 comprises aplurality of data connection ports and relays traffic from oneconnection port to another other in a transparent manner. Each data portis able to have a single network element connected to it. Switch 211operates in accordance with the networking protocol of the particularlocal area network that it serves, which in the case of the illustrativeembodiment is the Ethernet protocol. As those who are skilled in the artwill appreciate, however, in some alternative embodiments switch 211 canoperate in accordance with a networking protocol other than Ethernet,such as the IEEE 802.11 protocol. It will be clear to those skilled inthe art, after reading this specification, how to make and use switch211.

In accordance with the illustrative embodiment, switch 211 is capable ofswitching one or more data ports in full-duplex fashion, as is known inthe art. For each data port to which a network element is connected,such as router 102, full-duplex switching means that information cantravel from the connected device to switch 211 and from switch 211 tothe connected device simultaneously, provided that the connected deviceis also full-duplex capable. Furthermore, for each data port, switch 211is capable of configuring the data rates of the receive path andtransmit path independently of each other. As a result, the data rateselected for the receive path (i.e., the path from the connected deviceto the switch) can be either the same as or different from the data rateselected for the transmit path (i.e., the path from the switch to theconnected device). In some alternative embodiments, switch 211 iscapable of half-duplex switching only, as is known in the art, whichmeans that data can be transmitted in only one direction at a time.

As with network switch 101, enhanced network switch 211 is capable ofauto-negotiation at each data port. In accordance with the illustrativeembodiment, however, the rules that are used to ultimately determine thedata rates to take effect at certain data ports are different from thoserules used in auto-negotiation in the prior art. The rules of theillustrative embodiment are described in detail below and with respectto FIG. 4.

IP phone 212 is a telecommunications endpoint device that providesaccess for an end user to the local area network and to IP packetnetwork 103. IP phone 212 can be one of a SIP deskset, an H.323 terminalrunning on a personal computer, a laptop-based or desktop-basedsoftphone, and so forth. As a packet-based telephone, IP phone 212digitizes voice signals from its user and formats the digitized signalsinto transmittable data packets through an audio compressor/decompressor(or “CODEC”) circuit. Similarly, the CODEC circuit of IP phone 212 isalso capable of receiving data packets and converting the informationcontained within those packets into voice signals that areunderstandable by the endpoint user of IP phone 212. It will be clear tothose skilled in the art how to make and use IP phone 212.

In accordance with the illustrative embodiment, enhanced network switch211 and IP phone 212 are integrated into the same physical enclosure,such as that of a telephone deskset. This integration into a singleenclosure is intended to provide convenience to an end user by (i)providing switched local area network functionality and telephonyfunctionality in a single unit and (ii) pre-configuring the connectionbetween switch 211 and IP phone 212 within the unit. In some alternativeembodiments, however, switch 211 and IP phone 212 can be in separateenclosures and connected together by a cable that is visible to theuser.

FIG. 3 depicts the salient components of enhanced network switch 211 inaccordance with the illustrative embodiment of the present invention.Switch 211 comprises processor 301, memory 302, bus 303, upstream deviceport 304, IP phone port 305, and network element ports 306-1 through306-N, interconnected as shown. As those who are skilled in the art willappreciate, in some alternative embodiments the depicted elements ofswitch 211 comprise a different allocation of functionality across theelements or are interconnected differently than shown.

Processor 301 is a general-purpose processor that is capable ofreceiving information from one or more of the data ports (i.e., ports304, 305, and 306-1 through 306-N) via bus 303, executing instructionsstored in memory 302, reading data from and writing data into memory 302via bus 303, executing the tasks described below and with respect toFIG. 4, and transmitting information to one or more of the data portsvia bus 303. In some alternative embodiments of the present invention,processor 301 might be a special-purpose processor. In either case, itwill be clear to those skilled in the art, after reading thisspecification, how to make and use processor 301.

Memory 302 stores the instructions and data used by processor 301.Memory 302 might be any combination of dynamic random-access memory(RAM), flash memory, disk drive memory, and so forth. It will be clearto those skilled in the art, after reading this specification, how tomake and use memory 302.

Port 304 is capable of receiving packet signals from a connected,upstream device, which in this case is router 102, and of forwarding theinformation encoded in the signals to processor 301, in well-knownfashion. Port 304 is also capable of receiving information fromprocessor 301 and of transmitting signals that encode this informationto the connected, upstream device, in well-known fashion. As port 304 isintended for an upstream device, it can be labeled as such (e.g.,“Upstream”, “Internet”, etc.) so that a user properly connects the cablefrom the upstream device. It will be clear to those skilled in the art,after reading this specification, how to make and use port 304.

Port 305 is capable of receiving packet signals from a particular,connected, downstream device, which in this case is IP phone 212, and offorwarding the information encoded in the signals to processor 301, inwell-known fashion. Port 305 is also capable of receiving informationfrom processor 301 and of transmitting signals that encode thisinformation to the connected device, in well-known fashion. As port 305is intended for a particular type of downstream device, it can belabeled as such (e.g., “Phone”, etc.) so that the user properly connectsthe IP phone cable. It will be clear to those skilled in the art, afterreading this specification, how to make and use port 305.

Port 306-n, for n=1 through N, is capable of receiving packet signalsfrom a connected, generic network element, such as a user's personalcomputer or networked printer, and of forwarding the information encodedin the signals to processor 301, in well-known fashion. Port 306-n isalso capable of receiving information from processor 301 and oftransmitting signals that encode this information to the connecteddevice, in well-known fashion. It will be clear to those skilled in theart, after reading this specification, how to make and use port 306-n.

FIG. 4 depicts a flowchart of the salient tasks that are executed byenhanced network switch 211, in accordance with the illustrativeembodiment of the present invention. In accordance with the illustrativeembodiment, the term “first network element” refers to an upstreamdevice, the term “second network element” refers to a device whoseprocessor needs overload protection, and the term “third networkelement” refers to a device that does not fit into either of the firsttwo categories. For pedagogical purposes, router 102 is considered to bea first network element connected to switch 211, IP phone 212 isconsidered to be a second network element connected, and network element104-1 (e.g., a personal computer connected only for email, etc.) isconsidered to be a third network element connected. The first, second,and third network element nomenclature is referred to in the describedtasks, figures, and appended claims. As those who are skilled in the artwill appreciate after reading this specification, a differentcombination of network elements can represent the first, second, andthird network elements that are referred to herein. Furthermore, asthose who are skilled in the art will appreciate, some of the tasks thatappear in FIG. 4 can be performed in parallel or in a different orderthan that depicted.

At task 401, switch 211 receives a signal from the first networkelement, router 102, and the second network element, IP phone 212, whichdevices are connected to data ports of switch 211. In addition, switch211 might also receive a signal from the third network element, networkelement 104-1, if connected to a data port of switch 211. Each receivedsignal is part of an auto-negotiation sequence, which is well-known inthe art, and is used to convey data rate information about eachconnected network element.

In some embodiments, switch 211 also receives signals from one or moreof router 102, IP phone 212, and network element 104-1, if present,which signals convey information that correlates to the processor speed,or to some other attribute, of the connected network elements.

At task 402, switch 211 determines, in well-known fashion, that router102, IP phone 212, and device 104-1, if present, are each capable ofcommunicating at a first data rate (e.g., 10 Megabits/second, etc.) anda second data rate (e.g., 100 Megabits/second, etc.), where the firstdata rate is less than the second data rate. In accordance with theillustrative embodiment, the first data rate is the lowest data ratethat is supported by both router 102 and switch 211. However, as thosewho are skilled in the art will appreciate, in some alternativeembodiments, the first data rate can be the lowest data rate that issupported by all of router 102, switch 211, and another connectednetwork element, where the other connected element might be specificallyIP phone 212 or might be any device that is merely connected at apredetermined data port (i.e., port 305). In some other alternativeembodiments, the first data rate can be determined based on one or morecapabilities, such as processor speed, of IP phone 212, whichcapabilities have been communicated to switch 211.

Switch 211 might also determine that each connected device is able tocommunicate at additional data rates that are unique or in common withthe data rates that are supported by one or more of the other connecteddevices. The determination of the data rates is based on the signalsreceived at task 401. In some embodiments, switch 211 also determineswhether router 102 is capable of full-duplex communication with switch211 (i.e., is “full-duplex capable”), based on the signals received attask 401.

At task 403, if router 102 is full-duplex capable, task executionproceeds to task 404. Otherwise, task execution proceeds to task 406.

At task 404, if network elements other than a first network element anda second network element are connected to switch 211—for instance,element 104-1 is in fact connected—then task execution proceeds to task408. Otherwise, task execution proceeds to task 405.

At task 405, switch 211 establishes a link in the receive direction atthe first data rate between router 102 and switch 211, in accordancewith the illustrative embodiment of the present invention. Switch 211selects the link in the receive direction over a different link (e.g.,the link in the transmit direction to router 102, a link with adifferent network element, etc.) based on the determination that router102 is full-duplex capable. As those who are skilled in the art willappreciate, in some alternative embodiments, switch 211 can selectanother link or combination of links, such as setting both the transmitand receive links with router 102 to the first data rate. Furthermore,in some embodiments switch 211 selects the first data rate over thesecond data rate based on one or more of the following criteria havingbeen met:

-   -   i. exactly two devices are connected to switch 211;    -   ii. less than three devices are connected to switch 211;    -   iii. exactly two devices are connected to switch 211, where one        of the devices is an upstream device connected to port 304, such        as router 102;    -   iv. exactly two devices are connected to switch 211, where one        of the devices is a predetermined type, such as an end-user        telecommunications device;    -   v. any device is connected to a predetermined data port at        switch 211, such as port 305 that is reserved for IP phone 212;        and    -   vi. signals have been received (as described with respect to        task 401) that convey information that correlates to the        processor speed, or some other attribute, of a connected network        element such as IP phone 212.

As those who are skilled in the art will appreciate, the selection ofthe first data rate over the second data rate can be based on othercriteria not listed above and on other combinations of criteria.

In some embodiments, when router 102 and IP phone 212 are the onlynetwork elements that are connected to switch 211, the switch alsoestablishes a link in the transmit direction at the first data rate. Asthose who are skilled in the art will appreciate, the first data ratecan be selected for the link in the transmit direction, based on othercriteria such as the criteria already applied to the receive direction.In any event, task execution then proceeds to task 409.

At task 406, if network elements other than a first network element anda second network element are connected to switch 211—for instance,element 104-1 is in fact connected-then execution proceeds to task 408.Otherwise, task execution proceeds to task 407.

At task 407, switch 211 establishes a half-duplex link at the first datarate between router 102 and switch 211, in accordance with theillustrative embodiment of the present invention. Switch 211 selects thefirst data rate over the second data rate based on one or more of thefollowing criteria having been met:

-   -   i. exactly two devices are connected to switch 211;    -   ii. less than three devices are connected to switch 211;    -   iii. exactly two devices are connected to switch 211, where one        of the devices is an upstream device connected to port 304, such        as router 102;    -   iv. exactly two devices are connected to switch 211, where one        of the devices is a predetermined type, such as an end-user        telecommunications device;    -   vii. any device is connected to a predetermined data port at        switch 211, such as port 305 that is reserved for IP phone 212;        and    -   v. signals have been received (as described with respect to task        401) that convey information that correlates to the processor        speed, or some other attribute, of a connected network element        such as IP phone 212.        As those who are skilled in the art will appreciate, the        selection of the first data rate over the second data rate can        be based on other criteria not listed above and on other        combinations of criteria. In any event, task execution then        proceeds to task 409.

At task 408, switch 211 establishes a link between router 102 and switch211 at the highest data rate in common between the two devices, inwell-known fashion.

At task 409, if element 104-1 (i.e., the third network element) has beenconnected since the time that the link was established, task executionproceeds to task 410. Otherwise, task execution ends.

At task 410, switch 211 determines, in well-known fashion, that element104-1 is capable of communicating at the first data rate (e.g., 10Megabits/second, etc.) and the second data rate (e.g., 100Megabits/second, etc.). In some embodiments, the first data rate is thelowest data rate that is supported by both router 102 and IP phone 212.Switch 211 might also determine that element 104-1 is able tocommunicate at additional data rates that are unique or in common withthe data rates that are supported by one or more of the other connecteddevices. The determination of the data rates is based on the signalsreceived when element 104-1 was connected to switch 211.

At task 411, switch 211 reestablishes a link at the second data ratebetween router 102 and switch 211, in accordance with the illustrativeembodiment of the present invention. In accordance with the illustrativeembodiment, the second data rate is the highest data rate that issupported by both router 102 and switch 211. However, as those who areskilled in the art will appreciate, in some alternative embodiments, thesecond data rate can be the highest data rate that is supported by allof router 102, switch 211, and another connected network element, wherethe other connected element might be specifically IP phone 212 or mightbe any device that merely connected at a predetermined data port (i.e.,port 305). Switch 211 selects the second data rate over the first datarate based on a third device having been connected to the switch.

If router 102 is full-duplex capable, the link with router 102 thatswitch 211 reestablishes is the link in the receive direction. As thosewho are skilled in the art will appreciate, in some alternativeembodiments, switch 211 can select another link or combination of links,such as setting both the transmit and receive links with router 102 tothe second data rate. However, if router 102 is not full-duplex capable,switch 211 reestablishes a half-duplex link with router 102 at thesecond data rate. In any event, task execution ends after task 411.

It is to be understood that the above-described embodiments are merelyillustrative of the present invention and that many variations of theabove-described embodiments can be devised by those skilled in the artwithout departing from the scope of the invention. For example, in thisSpecification, numerous specific details are provided in order toprovide a thorough description and understanding of the illustrativeembodiments of the present invention. Those skilled in the art willrecognize, however, that the invention can be practiced without one ormore of those details, or with other methods, materials, components,etc.

Furthermore, in some instances, well-known structures, materials, oroperations are not shown or described in detail to avoid obscuringaspects of the illustrative embodiments. It is understood that thevarious embodiments shown in the Figures are illustrative, and are notnecessarily drawn to scale. Reference throughout the specification to“one embodiment” or “an embodiment” or “some embodiments” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment(s) is included in at least one embodimentof the present invention, but not necessarily all embodiments.Consequently, the appearances of the phrase “in one embodiment,” “in anembodiment,” or “in some embodiments” in various places throughout theSpecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, materials, orcharacteristics can be combined in any suitable manner in one or moreembodiments. It is therefore intended that such variations be includedwithin the scope of the following claims and their equivalents.

1. A method comprising: receiving, at a network switch, a first signalfrom a first network element and a second signal from a second networkelement, wherein said first network element is connected to a first dataport at said network switch, and wherein said second network element isconnected to a second data port at said network switch; determining thatsaid first network element and said second network element are eachcapable of communicating at least at a first data rate and a second datarate, wherein said first data rate is less than said second data rate;and establishing a link at said first data rate between said firstnetwork element and said network switch, wherein said first data rate isselected over said second data rate based on at least one of: (i) anetwork element being connected to said second data port, wherein saidsecond data port is predetermined, and (ii) said second network elementbeing connected to said network switch, wherein said second networkelement is predetermined.
 2. The method of claim 1 wherein said firstnetwork element is upstream of said network switch, and wherein saidsecond network element is an end-user telecommunications device.
 3. Themethod of claim 2 wherein said first data rate is selected over saidsecond data rate based on said second network element being connected tosaid second data port.
 4. The method of claim 3 wherein said networkswitch and said second network element are integrated into the samephysical enclosure.
 5. The method of claim 4 wherein said network switchand said second network element are integrated into a physical enclosureof a telephone deskset.
 6. The method of claim 2 further comprisingreceiving a third signal, which is from said second network element,wherein said third signal conveys information that correlates to theprocessor speed of said end-user telecommunications device.
 7. Themethod of claim 1 wherein when said first network element and saidnetwork switch are both full-duplex capable, said link that isestablished is specifically the receive path with respect to saidnetwork switch.
 8. The method of claim 1 wherein said first data rate isthe lowest data rate that is supported by both said first networkelement and said second network element.
 9. A method comprising:receiving, at a network switch, a first signal from a first networkelement and a second signal from a second network element, wherein saidfirst network element is connected to a first data port at said networkswitch, and wherein said second network element is connected to a seconddata port at said network switch; determining that said first networkelement and said second network element are each capable ofcommunicating at least at a first data rate and a second data rate,wherein said first data rate is less than said second data rate; andwhen said first network element and said second network element are theonly network elements connected to said network switch, establishing alink at said first data rate between said first network element and saidnetwork switch.
 10. The method of claim 9 further comprising: receiving,at said network switch, a third signal from a third network element,wherein said third network element is connected to a third data port atsaid network switch; determining that said third network element iscapable of communicating at least at said first data rate and saidsecond data rate; and reestablishing said link at said second data ratebetween said first network element and said network switch, wherein saidsecond data rate is selected over said first data rate based on saidthird network element being connected to said network switch.
 11. Themethod of claim 10 wherein said first network element is upstream ofsaid network switch, and wherein said second network element is anend-user telecommunications device.
 12. The method of claim 11 whereinsaid network switch and said second network element are integrated intothe physical enclosure of a telephone deskset.
 13. The method of claim11 further comprising receiving a fourth signal, which is from saidsecond network element, wherein said fourth signal conveys informationthat correlates to the processor speed of said end-usertelecommunications device.
 14. The method of claim 9 wherein when saidfirst network element and said network switch are both full-duplexcapable, said link that is established is specifically the receive pathwith respect to said network switch.
 15. A method comprising: receiving,at a network switch, a first signal from a first network element and asecond signal from a second network element, wherein said first networkelement is connected to a first data port that is full-duplex capable atsaid network switch, and wherein said second network element isconnected to a second data port at said network switch; determining that(i) said first network element is full-duplex capable and (ii) saidfirst network element and said second network element are each capableof communicating at least at a first data rate and a second data rate,wherein said first data rate is less than said second data rate; andestablishing, at said network switch, a link in the receive direction atsaid first data rate between said first network element and said networkswitch, wherein the establishment of said link in the receive directionis based on the determination that said first network element isfull-duplex capable.
 16. The method of claim 15 wherein said first datarate is selected over said second data rate based on a network elementbeing connected to said second data port.
 17. The method of claim 16further comprising when said first network element and said secondnetwork element are the only network elements connected to said networkswitch, establishing, at said network switch, a link in the transmitdirection at said first data rate between said first network element andsaid network switch, wherein said first data rate is selected over saidsecond data rate based on a network element being connected to saidsecond data port.
 18. The method of claim 15 further comprising:receiving, at said network switch, a third signal from a third networkelement, wherein said third network element is connected to a third dataport at said network switch; determining that said third network elementis capable of communicating at least at said first data rate and saidsecond data rate; and reestablishing, at said network switch, said linkin the receive direction at said second data rate between said firstnetwork element and said network switch, wherein said second data rateis selected over said first data rate based on said third networkelement being connected to said network switch.
 19. The method of claim18 wherein said first network element is upstream of said networkswitch, and wherein said second network element is an end-usertelecommunications device.
 20. The method of claim 19 wherein saidnetwork switch and said second network element are integrated into aphysical enclosure of a telephone deskset.
 21. The method of claim 18further comprising receiving a third signal, which is from said secondnetwork element, wherein said third signal conveys information thatcorrelates to the processor speed of said end-user telecommunicationsdevice.
 22. The method of claim 15 wherein said first data rate is thelowest data rate that is supported by both said first network elementand said second network element.